This invention relates to a lightweight deployable antenna system having the capability of operating at two frequencies. (2) Description of the Prior Art
Deployable antenna systems are conventionally used in a variety of settings and are especially favorable for marine applications in transmitting signals to other communication systems on installations or vessels. Many of such communication systems require that the antenna be able to transmit at one frequency and receive on another frequency, or that two different antennas be deployed. However, because of volume and weight complexity considerations, deployable antennas are structurally limited, thus leading to difficulties in achieving such functioning capabilities.
Most deployable antenna systems possess the ability to transmit and receive at only one frequency. An example of such a system is found in my U.S. Pat. No. 5,091,732. Other systems permit the antenna to be adjusted so as to have the capability of operating at more than one frequency, such as the system disclosed in U.S. Pat. No. 3,557,148. However, a problem inherent in such a system is that only a single frequency may be employed at a time. Additionally, such a system is intended to be used only for low frequency range applications and cannot accommodate higher frequency ranges which many communication systems call for. A collapsible antenna system is disclosed in U.S. Pat. No. 2,673,295. However, this system operates on a single frequency and is not intended for remote or automatic deployment.
Attempts have been made to reduce the volume of components in non-deployable antenna systems, such as the antenna systems of U.S. Pat. Nos. 4,031,539, 4,446,465, and 4,686,536. However, these systems employ fixed antenna arms which are not capable of being adjusted through a range of angles.
Other antenna systems of the non-deployable type employ different frequencies for transmitting and receiving electromagnetic radiation, such as the antenna system described in U.S. Pat. No. 3,702,479. However, this system also employs fixed elements which are not capable of being adjustably moved or deployed. Moreover, the operating frequencies for such a system are lower than those usually required for marine applications.
There is thus a need for a lightweight deployable antenna system which has the capability of operating at at least two frequencies.